After reading the first three quotes I thought this would be a fruitless search, but then things looked up.
I didn't persevere beyond four pages.
Group 1 = relevant to me, according to me.
Without friends no one would choose to live, though he had all other goods.
Aristotle (384 BC - 322 BC), Nichomachean Ethics
We must be willing to get rid of the life we've planned, so as to have the life that is waiting for us.
Joseph Campbell (1904 - 1987)
There can be no happiness if the things we believe in are different from the things we do.
Freya Madeline Stark
He who undervalues himself is justly undervalued by others.
William Hazlitt (1778 - 1830)
The only way to have a friend is to be one.
Ralph Waldo Emerson (1803 - 1882)
Group 2 = relevant further afield, according to me.
The highest proof of virtue is to possess boundless power without abusing it.
Lord Macaulay, review of Lucy Aikin, 'Life and Writings of Addison,' 1943
Patriotism is the last refuge of a scoundrel.
Samuel Johnson (1709 - 1784), quoted in Boswell's Life of Johnson
No matter what side of the argument you are on, you always find people on your side that you wish were on the other.
Jascha Heifetz (1901 - 1987)
Every decent (person) is ashamed of the government s/he lives under.
H. L. Mencken (1880 - 1956)
Some people are born on third base and go through life thinking they hit a triple.
Barry Switzer (1937 - )